[PATCH 6.9 236/374] nfc: nci: Fix uninit-value in nci_rx_work

Greg Kroah-Hartman
2024-06-06T14:10:17Z

From: Ryosuke Yasuoka <ryasuoka@redhat.com>

[ Upstream commit e4a87abf588536d1cdfb128595e6e680af5cf3ed ]

syzbot reported the following uninit-value access issue [1]

nci_rx_work() parses received packet from ndev->rx_q. It should be
validated header size, payload size and total packet size before
processing the packet. If an invalid packet is detected, it should be
silently discarded.

Fixes: d24b03535e5e ("nfc: nci: Fix uninit-value in nci_dev_up and nci_ntf_packet")
Reported-and-tested-by: syzbot+d7b4dc6cd50410152534@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=d7b4dc6cd50410152534 [1]
Signed-off-by: Ryosuke Yasuoka <ryasuoka@redhat.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/nfc/nci/core.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c
index b133dc55304ce..7a9897fbf4f41 100644
--- a/net/nfc/nci/core.c
+++ b/net/nfc/nci/core.c
@@ -1463,6 +1463,19 @@ int nci_core_ntf_packet(struct nci_dev *ndev, __u16 opcode,
ndev->ops->n_core_ops);
}

+static bool nci_valid_size(struct sk_buff *skb)
+{
+ BUILD_BUG_ON(NCI_CTRL_HDR_SIZE != NCI_DATA_HDR_SIZE);
+ unsigned int hdr_size = NCI_CTRL_HDR_SIZE;
+
+ if (skb->len < hdr_size ||
+ !nci_plen(skb->data) ||
+ skb->len < hdr_size + nci_plen(skb->data)) {
+ return false;
+ }
+ return true;
+}
+
/* ---- NCI TX Data worker thread ---- */

static void nci_tx_work(struct work_struct *work)
@@ -1516,7 +1529,7 @@ static void nci_rx_work(struct work_struct *work)
nfc_send_to_raw_sock(ndev->nfc_dev, skb,
RAW_PAYLOAD_NCI, NFC_DIRECTION_RX);

- if (!nci_plen(skb->data)) {
+ if (!nci_valid_size(skb)) {
kfree_skb(skb);
kcov_remote_stop();
break;
--
2.43.0